The parent grant for which this competing revision is being requested (AG026307-R01) evaluates longitudinal relationships between measures of self-regulation and self-control and measures of physical health in older adults, including peripheral markers of cardiovascular and immunological health. Critically, however, older adults high in self-regulation (e.g., conscientiousness) also demonstrate positive health outcomes that implicate improved central nervous system/brain health, such as reduced risk for Alzheimer's disease, slower cognitive decline, and increased longevity. Despite this apparent link to successful brain aging, relationships between individual differences in trait self-regulation and brain structure and function have not been studied to date. The parent study longitudinally and repeatedly assesses self-regulation and health in older adults (current N=135). Here we seek to broaden this well-established study with multi-modal magnetic resonance imaging (MRI) measures of brain structure and function. The proposed project stands to bridge the knowledge gap between personality and behavioral variants associated with superior health outcomes in older adults and the determinants of successful brain aging. The proposed project will: 1) Examine whether better self-regulation correlates with less evidence of brain structural decline. We and others have shown that healthy behaviors, such as exercise, promote the integrity of white matter tracts and protect against atrophy in the brain. Here volumetric and diffusion tensor imaging will be used to assess relationships between brain structure, self-regulation, and potential behavioral mediators (including physical activity and other healthy behaviors). 2) Examine whether better self-regulation is associated with more youthful brain function. A more youthful pattern of brain activation in older age is one important marker of successful cognitive aging. In our previous work, we have shown that high performing older adults exhibit more youthful patterns and levels of functional activation during cognitive control tasks. Moreover, we have shown that older adults protected by advantageous cognitive traits (e.g., lifelong bilingualism), as a group, exhibit more youthful activation and superior cognitive control task performance compared to age-matched peers. 3) Examine whether better self-regulation correlates with successful compensatory patterns of brain activity. Successful cognitive task performance in older adults is often accompanied by reorganized patterns of brain activation and functional connectivity. Such changes are thought to reflect the functional plasticity of the aging brain and likely reflect a shift in the cognitive strategies used to perform cognitive tasks. Since not all older adults express such compensatory changes, it is important to understand the role that psychological resources, e.g., self-regulation, play in promoting successful adaptation to brain aging.